The Roth feature means you can contribute post-tax dollars into the plan so you won’t have to pay taxes on these contributions when you take them out.
When you contribute to a traditional 401(k), you’re contributing on a pre-tax basis, meaning you get a tax break upfront but have to pay taxes when you take the money out in retirement. With a Roth account, you contribute post-tax dollars, and the money you contribute, including earnings (if you hold the account for at least five years and don’t withdraw the money until at least age 59½), comes out tax-free in retirement.
Who would want to take advantage of the Roth feature? You, if you:
If you take advantage of the Roth feature, your post-tax contributions will go into a separate account, which is different than any pre-tax contributions you make.